The evolutionary development of mobile networks has resulted in advanced technologies for both the handset as well as wireless access to the base stations. This development has provided users with unprecedented data rates enabling various types of rich multimedia services to be realised (e.g. high definition video conferencing). By 2020, the IP data handled by wireless networks is expected to exceed 500 exabytes. The expectations of 5G systems are planned towards high capacity communication links (10 Gbps) that can provide users access to numerous types of application (e.g. augmented reality, holographic multimedia streaming) Other requirements of these next-generation networks, include end-user Quality of Service (QoS), energy efficiency, green communication systems and flexible management of resources. Maintaining a high QoS over infrastructure that supports mobility of users (or groups of users) migrating between locations requires frequent handovers for roaming. The network management of 5G networks is moving towards decoupling the data and control plane through Software-Defined Networking (SDN) as well as Network Function Virtualization (NFV).
While new forms of software development are being planned for 5G systems, there is also a need to discover new wireless technologies between the handset and the base stations that are able to handle very high speed transmission. One approach that is being investigated is to push the carrier frequencies into the terahertz (THz) band. The THz band is the spectral band that spans the frequencies between 0.1 THz and 10 THz.
Terahertz band communication has many challenges including the need for Line-of-Sight (LoS) links, the loss of signal strength due to molecular absorption depending on weather conditions and issues with the frequency response due to the Doppler Effect. Typically, when signals are transmitted in the terahertz band, the data rate drops considerably for non-line of sight connections (NLoS) due to reflection and/or scattering losses on rough surfaces. Multi-path propagations and the Doppler Effect are also known to present problem for outdoor Terahertz band communication systems and are considered highly challenging to system performance.
Some work has been done on systems for terahertz band communication. For example, U.S. Pat. No. 9,397,758 to Georgia Tech Research Corporation et al proposes a graphene-based plasmonic nano-transceiver for terahertz communication. US2016/218464 also to Georgia Tech Research Corporation proposes a graphene-based plasmonic nano-antenna for terahertz communication. A paper entitled “Three-dimensional End-to-End Modelling and Analysis for Graphene-Enabled Terahertz Band Communications” by Chong Han and Ian Akyildiz published in IEEE Transactions on Vehicular Technology, Special Section on THz Communication for Vehicular Networks (DOI: 10.1109/TVT.2016.2614335), 2017 investigates a graphene-based reflectarray antenna.